The Exclusivity of Multivalency in Dynamic Covalent Processes

Badjić, Jovica D.; Cantrill, Stuart; Grubbs, Robert H.; Guidry, Erin N.; Orenes, Raúl A.; Stoddart, J. Fraser

doi:10.1002/anie.200453963

Cited by 72 publications

(17 citation statements)

References 63 publications

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“…The relevant intramolecular metathesis condensation of a linear poly(THF) having allyl end groups has been recently performed under dilution in the presence of a Grubbs catalyst, ruthenium( II ) dichloride phenylmethylene bis(tricyclohexylphosphine) [RuCl 2 (PCy 3 ) 2 (CHPh)], to produce a cyclic poly(THF) effectively 14. It is also worth noting that the intramolecular metathesis condensation of small‐ to medium‐size molecules having multiple olefinic groups has been employed for the construction of a variety of complex loop topologies 15–18…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Tezuka

Ohashi

2005

Macromol. Rapid Commun.

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Summary: An H‐shaped poly(tetrahydrofuran), poly(THF), having four terminal allyl groups was prepared through the covalent conversion of an ionically linked polymer assembly, comprised of four units of cationic poly(THF) having a pyrrolidinium salt and an allyl end group, and one unit of anionic poly(THF) having two dicarboxylate end groups. A pair of polymeric topological isomers, having double‐cyclic, manacle, and θ‐shaped constructions, was subsequently produced under dilution through the intramolecular double metathesis condensation of four terminal allyl groups of the H‐shaped precursor.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Tezuka

Ohashi

2005

Macromol. Rapid Commun.

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“…Recently, dynamic covalent chemistry (37)(38)(39)(40), exemplified by reversible imine formation (41,42), metal-ligand exchange (43), and olefin metathesis (44,45), has been demonstrated to be an effective tool for the preparation of various exotic mechanically interlocked molecular compounds. It has been found that, in the presence of an appropriate template, one of the possible compounds in the dynamic library, after mixing the different components, can be amplified to give the thermodynamically most stable product.…”

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confidence: 99%

Efficient production of [ n ]rotaxanes by using template-directed clipping reactions

Leung

Stoddart

2007

Proc. Natl. Acad. Sci. U.S.A.

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119

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In this article, we report on the efficient synthesis of well defined, homogeneous [n]rotaxanes (n up to 11) by a template-directed thermodynamic clipping approach. By employing dynamic covalent chemistry in the form of reversible imine bond formation, [ dynamic covalent chemistry ͉ molecular recognition ͉ polyrotaxanes ͉ self-assembly ͉ template-directed synthesis M echanically interlocked and knotted compounds, such as rotaxanes (1-5), catenanes (6-10), suitanes (11, 12), trefoil knots (13-17), , and Solomon knots (21), represent challenging synthetic goals that have nevertheless been realized. These molecular compounds are usually synthesized by a template-directed approach (22) that depends on molecular recognition and self-assembly processes. Recently, their potential applications as molecular switches for nanoelectronics (23, 24) and molecular actuators for constructing artificial muscles (25), for fabricating smart surface materials (26), and for controlling the nanoscale release of molecules trapped in mesoporous silica (27)(28)(29) were demonstrated. Polyrotaxanes and well defined, homogeneous oligorotaxanes, in which the recognition sites on a dumbbell (an axle terminated by bulky stoppers) are encircled by large rings or macrocycles (wheels) by dint of molecular recognition, have become (30-36) one of the most intensively investigated subjects in mechanical chemistry. A general synthetic method for making rotaxanes, namely, the ''threading-followed-by-stoppering'' approach (Fig. 1, method A), involves (30-32) several macrocycles. First, the macrocycles are threaded onto oligomeric or polymeric axles carrying recognition sites at prescribed intervals along the axles to form pseudorotaxanes, then both ends of the axles are stoppered with bulky groups. Although this approach is relatively simple, it does not provide complete control over the number of threaded macrocycles, that is, the rings or beads are often not threaded onto all of the available recognition sites on the axles. Alternatively, a template-directed ''clipping'' approach (Fig. 1, method B), in which the macrocycles are formed from acyclic precursors in the presence of templating recognition sites on the dumbbells, has provided (33-36) a versatile means for the construction of some lower-order rotaxanes. Nonetheless, the efficient synthesis of well defined, homogeneous, higher-order polyrotaxanes continues to be a challenge to synthetic chemists.Recently, dynamic covalent chemistry (37-40), exemplified by reversible imine formation (41, 42), metal-ligand exchange (43), and olefin metathesis (44, 45), has been demonstrated to be an effective tool for the preparation of various exotic mechanically interlocked molecular compounds. It has been found that, in the presence of an appropriate template, one of the possible compounds in the dynamic library, after mixing the different components, can be amplified to give the thermodynamically most stable product. We have reported (see refs. 46-49) an example of such a template-directed synthesis of ...

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“…Many reversible reactions, including the formation of imines, disulfides, and cyclic acetals, as well as olefin metatheses, have been employed as the final reaction steps to synthesize catenanes and rotaxanes 10. Especially, the construction of magic‐ring catenanes5c and magic‐rod rotaxanes11 by olefin metathesis has been recently reported. However, synthesis of more complex interlocked molecules by means of the DCC strategy is still a challenge.…”

Section: Methodsmentioning

confidence: 99%

Multivalency‐Directed Magic‐Ring [2](3)Catenane by Olefin Metathesis

Jiang

Zhu

Chen

2010

Chemistry A European J

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[a] Multivalency, [1] as a way to compensate for the weak monovalent interactions in nature, has attracted considerable interest in recent years.[2] Chemists tried to discover the physical basis of multivalency effects based on a thermodynamic model combined with computational studies and found that thermodynamics play a key role as far as multivalent interactions is concerned.[3] The construction of supermolecules by the bottom-up approach to mimic biomacromolecules and their assemblies is one of the main aims for supramolecular chemists.[4] Although multivalency provides a fascinating inspiration for chemists seeking to transfer concepts from the biological world into supramolecular chemistry, there are still very few examples of multivalency in the noncovalent synthesis of various elaborate supermolecules. [5] Mechanically interlocked molecules, [6] such as catenanes and rotaxanes, are not only aesthetically pleasing curiosities, but can function as the key components in future "intelligent" materials.[7] Although a vast number of syntheses of catenanes and rotaxanes have been reported, most of the strategies employ kinetically controlled covalent-bond formation as the final interlocking steps in which the product distribution relies on kinetic rather than thermodynamic control.[8] Therefore, chemists have exploited dynamic covalent chemistry (DCC) [9] as an alternative strategy that utilizes reversible reactions as the final interlocking step in which the product distribution relies on thermodynamic rather than kinetic control. Many reversible reactions, including the formation of imines, disulfides, and cyclic acetals, as well as olefin metatheses, have been employed as the final reaction steps to synthesize catenanes and rotaxanes. [10] Especially, the construction of magic-ring catenanes [5c] and magic-rod rotaxanes [11] by olefin metathesis has been recently reported. However, synthesis of more complex interlocked molecules by means of the DCC strategy is still a challenge.In recent years, we became interested in developing new supramolecular systems based on triptycene-derived synthetic hosts.[12] As a result, we reported a highly efficient approach to synthesize [2](3)catenanes by threefold metathesis reactions of a triptycene-based tris[2]pseudorotaxane. [13,14] Herein, we report formation of a novel multivalency-directed complex 1·2-3 H·PF 6 composed of the trisdialkylammonium strand ions 2-3 H·PF 6 and the triptycene-based homotritopic host 1, [13a] containing three dibenzo[24]crown-8 cavities, and the subsequent [2](3)catenane 4-3 H·3 PF 6 by the olefin metathesis reaction. Moreover, we also designed and synthesized a trisdialkylammonium macrocycle ion, 3-3 H·PF 6 , and found that it could form an interesting magicring [2](3)catenane with the homotritopic host 1 by reversible olefin metathesis (Scheme 1).Scheme 2 outlines the synthesis of the trisdialkylammonium strand ions 2-3 H·PF 6 . Condensation of the amine 10 with the aldehyde 9 gave the corresponding imine, which was reduced by...

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The Exclusivity of Multivalency in Dynamic Covalent Processes

Cited by 72 publications

References 63 publications

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Efficient production of [ n ]rotaxanes by using template-directed clipping reactions

Multivalency‐Directed Magic‐Ring [2](3)Catenane by Olefin Metathesis

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